Anybody running 285/65/r18?

wondering if anyone else has put these on? At 14.7 mpg with only 580 miles on the truck. Im hoping it goes up once things break in. If not what's everybody think about changing the gearing since this transmission is way too busy? I have been reading a lot on here and to me this truck seems a lot like a new girlfriend she's new and different. My 06 gen 2 is still alive a well 230k zero issues except that plug for the a/c on the floorboard by the pass feet!! I'm having a hard time remembering how my gen 2 acted fresh off the lot. I took it right in for intake,headers and exhaust then drove to cali to have the guys at underdog tune the air to fuel ratio.